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Submission #906047

# Submission time Handle Problem Language Result Execution time Memory
906047 2024-01-13T11:56:03 Z Mathias The Xana coup (BOI21_xanadu) C++14
30 / 100
 58 ms 20820 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int MAXN = 1e5+7;
const long long INF = 1e18+7;
long long dp[MAXN][3][3];
bool t[MAXN], visited[MAXN];
vector<long long> g[MAXN];
long long n,a,b,c,d;
void DFS(int x,int f){
	visited[x]=1;
	if(t[x]){
		dp[x][1][0]=1;
		dp[x][0][1]=0;
	}
	else{
		dp[x][1][1]=1;
		dp[x][0][0]=0;
	}
	for(int i=0;i<g[x].size();i++){
		if(visited[g[x][i]]==1) continue;
		int s=g[x][i];
		DFS(s,x);
	}
	for(int i=0;i<g[x].size();i++){
		int s=g[x][i];
		if(s==f) continue;
		a=dp[x][0][0], b=dp[x][0][1], c=dp[x][1][0], d=dp[x][1][1];
        dp[x][0][0]=min(a+dp[s][0][0], b+dp[s][1][0]);
        dp[x][0][1]=min(b+dp[s][0][0], a+dp[s][1][0]);
        dp[x][1][0]=min(c+dp[s][0][1], d+dp[s][1][1]);
        dp[x][1][1]=min(d+dp[s][0][1], c+dp[s][1][1]);
	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin>>n;
	for(int i=1;i<n;i++){
		cin>>a>>b;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	for(int i=1;i<=n;i++) cin>>t[i];
	for(int i=1;i<=n;i++){
		dp[i][0][0]=INF;
		dp[i][1][0]=INF;
		dp[i][0][1]=INF;
		dp[i][1][1]=INF;
	}
	DFS(1,0);
	if(dp[1][1][0]>n and dp[1][0][0]>n) cout<<"impossible\n";
	else cout<<min(dp[1][1][0], dp[1][0][0])<<'\n';
	return 0;
}

Compilation message

xanadu.cpp: In function 'void DFS(int, int)':
xanadu.cpp:20:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~
xanadu.cpp:25:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 2 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 2 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4696 KB Output is correct
7 Correct 2 ms 4696 KB Output is correct
8 Correct 2 ms 4696 KB Output is correct
9 Correct 1 ms 4700 KB Output is correct
10 Correct 1 ms 4700 KB Output is correct
11 Correct 1 ms 4696 KB Output is correct
12 Correct 2 ms 4700 KB Output is correct
13 Correct 1 ms 4700 KB Output is correct
14 Correct 2 ms 4700 KB Output is correct
15 Correct 2 ms 4700 KB Output is correct
16 Correct 1 ms 4700 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 58 ms 20820 KB Output is correct
2 Correct 42 ms 20316 KB Output is correct
3 Correct 41 ms 20540 KB Output is correct

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 49 ms 20564 KB Output is correct
2 Correct 52 ms 20368 KB Output is correct
3 Correct 40 ms 20572 KB Output is correct
4 Incorrect 39 ms 13904 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4700 KB Output is correct
2 Correct 2 ms 4700 KB Output is correct
3 Correct 1 ms 4700 KB Output is correct
4 Correct 1 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 1 ms 4696 KB Output is correct
7 Correct 2 ms 4696 KB Output is correct
8 Correct 2 ms 4696 KB Output is correct
9 Correct 1 ms 4700 KB Output is correct
10 Correct 1 ms 4700 KB Output is correct
11 Correct 1 ms 4696 KB Output is correct
12 Correct 2 ms 4700 KB Output is correct
13 Correct 1 ms 4700 KB Output is correct
14 Correct 2 ms 4700 KB Output is correct
15 Correct 2 ms 4700 KB Output is correct
16 Correct 1 ms 4700 KB Output is correct
17 Correct 58 ms 20820 KB Output is correct
18 Correct 42 ms 20316 KB Output is correct
19 Correct 41 ms 20540 KB Output is correct
20 Correct 49 ms 20564 KB Output is correct
21 Correct 52 ms 20368 KB Output is correct
22 Correct 40 ms 20572 KB Output is correct
23 Incorrect 39 ms 13904 KB Output isn't correct
24 Halted 0 ms 0 KB -